When I was building the MRX Ultra, I noticed something was a bit off with the caster on my car. No matter what, the two sides were not the same. After tearing everything down again, I found that this problem was caused by the knuckles. Long story short, the two threaded bits did not line up, causing about a degree of difference in caster.
Fast forward to today when I received a box of goodies from Atomic that included a new set of knuckles, knuckle ball shims and a set of tuning springs.
The first thing you’ll probably notice is that the new knuckles are black and have the same sort of finish as the arms. Personally, I liked the raw color better but this is an easy way to tell the old and new ones apart, and, come on, they’re knuckles. Who cares what color they are?
When rebuilding the knuckles, I used Atomic’s new 0.5mm knuckle ball shims. These are made out of plastic and have a smaller outer diameter (3.0mm vs ~3.4mm) than the metal ones to reduce wheel rub.
I also need to make a correction regarding the rear springs in my tip from last week. The yellow spring in my picture was not the correct one. I pulled it out of the box containing all of my MRX Master parts but it was much stiffer than the actual rear spring.
Here is a picture of the correct springs. From left to right, you have white, yellow, purple and stock. Using my super scientific finger squish test, the stock spring feels like the stiffest of the bunch. I’m currently running the white on my stock spec car but will be testing yellow and purple as well as the new side springs this week. Check back for updates!